1. Field of the Invention
The present invention is generally related to mail sorting systems and, more particularly, to an apparatus which may either retain mail sacks of varying sizes in their open position or hold mail trays such that parcels and bundles can be collected in the mail sacks or trays.
2. Description of the Prior Art
The small parcel and bundle sorting system presently used by the United States Postal Service employs only plastic trays or large wire containers to collect sorted mail. The sorting system would be more versatile if mail sacks could be used as an alternate receptacle for receiving sorted mail pieces. Even greater utility would be realized from a system which readily converted between a sack or tray output system.
In order to use mail sacks in conjunction with the small parcel and bundle sorting system, the mail sacks would need to be held open and upright such that mail could be dropped into the sack from the sorting chute.
Racks for holding a sack open to receive packages or parcels are known in the art. Most sack racks utilize the metal eyelets which are present about the top periphery of mail sacks. The metal eyelets are typically hooked to the sack rack such that the top of the sack is held open. Hooking the metal eyelets of a mail sack to a rack system is not a convenient method for use in the small parcel and bundle sorting system environment. The volume of mail handled at mail processing centers is very large and the collecting receptacles must be changed frequently as they are filled with mail. A sweep attendant could experience difficulty in unhooking the eyelets of a filled mail sack and then hooking the eyelets of an empty mail sack at rates that accommodate the processing rate of the of the sorting machine.
The Post Office uses mail sacks of varying sizes. For example, the air mail parcel post sack used by the Post Office has a sack opening of fifteen inches by fifteen inches, whereas the air mail and first class mail sacks have sack openings of fifteen inches by ten and one quarter inches. Sack racks which use stationary hooks to hold a mail sack open by its metal eyelets are not versatile enough to handle the varying sizes of mail sacks used by the Post Office. A smaller mail sack, such as a first class mail sack, could not be hooked to a rack sized to handle a larger mail sack, such as an air mail parcel post sack, because the smaller sack could not be opened wide enough for the hooks to fasten to the metal eyelets of the sack. Likewise, a larger mail sack could not be hooked to a rack sized to handle a smaller mail sack because the larger mail sack would tend to fold inwardly and block off the sack opening from receiving the sorted mail.
A need exists for a sack rack which can be used with the small parcel and bundle sorting system. The sack rack must be designed to allow a sweep attendant to quickly change mail sacks and to accommodate mail sacks of varying sizes. In addition, the sack rack should be quickly convertible between sack sorting and tray sorting receptacles.